1. Field of the Disclosure
This disclosure is related to an optical encoder and an operating method thereof that provide precise coding reference data by feature recognition technology. The precise coding reference data can be generated by detecting surface features of a working surface without providing particular dense patterns on the working surface or any reference object with particular markers.
2. Description of the Related Art
Conventionally, means for optical encoding generally needs to process a working surface to have markers with a specific density for reflecting light or light penetration. Or the encoding is implemented by arranging light sources in a particular way or controlling the light emitting sequence. For example, U.S. Pat. No. 8,598,509 discloses a plurality of light sources for emitting light in a particular sequence as well as an encoded working surface with predetermined gaps such that the light can penetrate the gaps in a predetermined manner to be detected by a photodetector. The detection result is used to generate the coding reference data, e.g. position data or velocity data of some elements in the system.
However, in this conventional technology a special processing has to be performed on the working surface previously such that the application thereof is limited. Meanwhile, in order to obtain an accurate detection result, the processing of the working surface becomes complicated so that the difficulty of applying this technology also becomes higher.